1. Field of the Invention
This invention relates to the field of digital image processing.
2. Description of the Related Arts
Digital image processing techniques have major features of easy image editing and modifications.
FIGS. 16, 17, and 18 are conceptual diagrams showing the configuration of such prior art image automatic correction software.
Usually an editor (operator) performs various operations on an original image with the aid of such software, thereby obtaining a desired image in a trial and error fashion.
In such a process, an image at each step in which an original image is subjected to different processing as shown in FIG. 17 is saved, and if a desired image is not obtained by processing in one way, processing is often performed again from the beginning or performed on an intermediate image in a different way.
In the process of the operations, carefully making records of an original image pertaining to image data created at each step, information about processing on the images, and other information may avoid confusion, but an editor often concentrates attention to processing itself and neglects such recording, so that data at intermediate steps is disorderly accumulated, with the result that the intermediate data cannot be reused. For this reason, operations that have been heretofore performed often become meaningless.
In the case where a plurality of images are processed at a time as in automatic image correction software as shown in FIG. 18, the same problem as described above occurs since it cannot be determined what processing the program performed on each image.
Furthermore, also when image data is passed to different editors, the editors will perform similar operations because the history of the image data is not always clear.
Although an image produced as a result of image processing may be intuitively different from an original image thereof, it cannot be practically determined visually what processing has been performed to produce the image, what the original image was like, which of two pieces of data, if any, is the original image, and the like.
Presently, numerous file formats of images are proposed and some of them permit predetermined information to be written in advance in a predetermined area (tag) of a file. However, some file formats do not have such an area or have no area corresponding to information to be written; these formats are inconvenient to use because desired information cannot be recorded.
The U.S. Pat. No. 5,530,759 by Gordon et al discloses a system for placing a visible “watermark” on a digital image, wherein an image of the watermark is combined with the digital image.
The pixels of the watermark image are examined, and for each pixel whose value is not a specified “transparent” value, the corresponding pixel of the original image is modified by changing its brightness but its chromaticities. This results in a visible mark which allows the contents of image to be viewed clearly, but which discourages unauthorized use of the image.
The important matter of this patent is that the contents of image are visible and thereby the unauthorized use of the image is prevented.